From: Takashi Iwai <tiwai@suse.de>
To: Runyu Xiao <runyu.xiao@seu.edu.cn>
Cc: Clemens Ladisch <clemens@ladisch.de>,
Jaroslav Kysela <perex@perex.cz>, Takashi Iwai <tiwai@suse.com>,
stable@vger.kernel.org, Jianhao Xu <jianhao.xu@seu.edu.cn>,
linux-sound@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH v2] ALSA: usb-audio: Protect Roland control activation
Date: Tue, 29 Sep 2026 16:27:10 +0200 [thread overview]
Message-ID: <87y0ckyvy9.wl-tiwai@suse.de> (raw)
In-Reply-To: <20260929141726.2166899-1-runyu.xiao@seu.edu.cn>
On Tue, 29 Sep 2026 16:17:26 +0200,
Runyu Xiao wrote:
>
> The USB MIDI driver changes the Roland MIDI Input Mode control's access
> flags directly from the rawmidi open and close paths. These changes are
> not protected by the ALSA control core and the corresponding notifications
> can race with control access.
>
> Use snd_ctl_activate_id() so that the control core updates the access flags
> and sends the notification under its lock. Release the USB MIDI mutex
> before calling it because the control write path holds controls_rwsem while
> roland_load_put() takes the USB MIDI mutex.
>
> Keep the state transition and alternate-setting change under the USB MIDI
> mutex; rawmidi's open mutex serializes the enclosing open and close paths.
>
> Fixes: 96f61d9ade82 ("sound: usb-audio: allow switching altsetting on Roland USB MIDI devices")
> Cc: stable@vger.kernel.org
> Assisted-by: LLM
> Signed-off-by: Runyu Xiao <runyu.xiao@seu.edu.cn>
Applied to for-next branch. Thanks.
Takashi
prev parent reply other threads:[~2026-09-29 14:27 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-09-29 7:40 [PATCH] ALSA: usb-audio: Protect Roland control activation Runyu Xiao
2026-09-29 13:34 ` Takashi Iwai
2026-09-29 14:17 ` [PATCH v2] " Runyu Xiao
2026-09-29 14:27 ` Takashi Iwai [this message]
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